Sending units are a good junkyard item. It also gives you practice taking off the retainer ring that holds the intank pump/sending unit assembly to the top of the fuel tank, if you haven't done this before. Spray some PBlaster on it before you try knocking the ring around. Clean the area first and be careful not to get dirt in the tank. You might want to just get the entire assembly (plus the retaining ring) from the junkyard, so you'll have the extra ring and intank pump if you ever need one.

Sending unit failure is probably the most common problem with none working fuel gauge. It is inside the gas tank. On my 1990 disconnecting and grounding a gray wire located in trunk area verifies that gauge and wiring is ok.